1. Technical Field
The present invention relates to a resist pipe and a resist coating device, and more specifically relates to a resist pipe of a resist coating device that is employed in a lithography process in fabrication of an integrated circuit, and relates to that resist coating device.
2. Related Art
Heretofore, in a process of fabrication of a semiconductor device, that is, an integrated circuit such as an IC, an LSI, a ULSI or the like, generally, a photolithography technology has been used to implement formation of a predetermined pattern on a substrate to be processed, which is, for example, a semiconductor substrate (such as a silicon wafer) (see, for example, Japanese Patent Application Laid-Open (JP-A) No. 2000-84468).
In this photolithography technology, a resist film is coated to a main surface of the semiconductor substrate. A resist coating device is used for the coating of the resist film. Commonly, a spin-coating method is used in the coating of the resist film by the resist coating device. That is, the semiconductor substrate is loaded on a spin chuck, the resist coating device is used to drip resist liquid to a central portion of the semiconductor substrate, after which the spin chuck is rotated at high speed. The resist liquid is spread from the central portion to a peripheral portion of the semiconductor substrate by centrifugal force caused by the rapid rotation of the semiconductor substrate, and the resist film is coated uniformly to the overall surface of the semiconductor substrate.
As shown in FIG. 7, a resist supply portion 120, which supplies the resist liquid to the resist coating device, is provided with, for example, a liquid level sensor portion 130 as described in JP-A No. 8-219853. When a remaining amount of a resist liquid 116 in a gallon bottle 114 falls, it is detected by the liquid level sensor portion 130, and an inhalation of air by the resist supply portion 120 due to the falling of a liquid level 116A is prevented. The liquid level sensor portion 130 and the resist supply portion 120 are inserted into the gallon bottle 114 or the like respectively separately.
As shown in FIG. 8A and FIG. 8B, when the falling of the liquid level of the resist liquid 116 is not detected by the liquid level sensor portion 130 and that air is inhaled by the resist supply portion 120, it is possible that a proper resist dripping amount may not be provided due to the mixing in of air in the resist coating process, and coating failures occur. Structures for eliminating air bubbles that have been mixed into the resist have been proposed (see, for example, JP-A No. 2005-136186), but are not capable of preventing mixing of air into the liquid.
Moreover, as shown in FIG. 8C and FIG. 8D, when the liquid level sensor portion 130 mistakenly detects the liquid level 116A even when an amount remains (misdetection), there is no effect on the product. However, problems remain such as a reduction in efficiency and an increase in man-hours due to operations being interrupted, the impossibility of detecting when the liquid amount will actually fall, and so forth.
The above-described problems are caused by positions of the leading end of the resist supply portion and the liquid level sensor portion being separated. Therefore, to solve these problems, it is necessary to close up the two.